Show the percentage of CPU utilization that occurred while executing at the user level (application).

%nice

Show the percentage of CPU utilization that occurred while executing at the user level with nice priority.

%system

Show the percentage of CPU utilization that occurred while executing at the system level (kernel).

%iowait

Show the percentage of time that the CPU or CPUs were idle during which the system had an outstanding disk I/O request.

%steal

Show the percentage of time spent in involuntary wait by the virtual CPU or CPUs while the hypervisor was
servicing another virtual processor.

%idle

Show the percentage of time that the CPU or CPUs were idle and the system did not have an outstanding disk I/O request.

-c

Display the CPU utilization report.

-d

Display the device utilization report.

-g

group_name { device […] | ALL } Display statistics for a group of devices. The iostat command reports statistics for each individual device in the list then a line of global statistics for the group displayed as group_name and made up of all the devices in the list. The ALL keyword means that all the block devices defined by the system shall be included in the group.

-h

Make the Device Utilization Report easier to read by a human.

-j

{ ID | LABEL | PATH | UUID | … } [ device […] | ALL ] Display persistent device names. Options ID, LABEL, etc. specify the type of the persistent name. These options are not limited, only prerequisite is that directory with required persistent names is present in /dev/disk. Optionally, multiple devices can be specified in the chosen persistent name type. Because persistent device names are usually long, option

-H

This option must be used with option -g and indicates that only global statistics for the group are to be displayed, and not statistics for individual devices in the group. -h is enabled implicitly with this option.

[ { device [,…] | ALL } ]
The -p option displays statistics for block devices and all their partitions that are used by the system. If a device name is entered on the command line, then statistics for it and all its partitions are displayed. Last, the ALL keyword indicates that statistics have to be displayed for all the block devices and partitions defined by the system, including those that have never been used. If option -j is defined before this option, devices entered on the command line can be specified with the chosen persistent name type.

-t

Print the time for each report displayed. The timestamp format may depend on the value of the S_TIME_FORMAT environment variable (see below).

-V

Print version number then exit.

-x

Display extended statistics.

-y

Omit first report with statistics since system boot, if displaying multiple records at given interval.

-z

Tell iostat to omit output for any devices for which there was no activity during the sample period.